PDF(Pubmed)
Abstract：
We investigated long-term human coagulation factor IX (huFIX) expression of a novel variant when delivered into mice and rhesus macaques and compared transduction efficiencies using two different adeno-associated virus (AAV) capsids. In hemophilic mice injected with KP1-packaged recombinant AAV (rAAV) expressing the hyperactive FIX variant specific activity plasma levels were 10-fold or 2-fold enhanced when compared with wild-type or Padua huFIX injected mice, respectively. In rhesus macaques AAV-LK03 capsid outperformed AAV-KP1 in terms of antigen expression and liver transduction. Two animals from each group showed sustained low-level huFIX expression at 3 months after administration, while one animal from each group lost huFIX mRNA and protein expression over time, despite comparable vector copies. We investigated whether epigenetic differences in the vector episomes could explain this loss of transcription. Cut&Tag analysis revealed lower levels of activating histone marks in the two animals that lost expression. When comparing rAAV genome associated histone modifications in rhesus macaques with those in mice injected with the same vector, the activating histone marks were starkly decreased in macaque-derived episomes. Differential epigenetic marking of AAV genomes may explain different expression profiles in mice and rhesus macaques, as well as the wide dose response variation observed in primates in both preclinical and human clinical trials.
摘要：
我们研究了一种新型变体在递送到小鼠和恒河猴中时的长期人凝血因子IX表达，并使用两种不同的AAV衣壳比较了转导效率。与野生型或PaduahuFIX注射小鼠相比，在注射了表达过度活跃FIX变体比活性的KP1包装的rAAV的血友病小鼠中，血浆水平提高了10倍或2倍，分别。在恒河猴中，AAV-LK03衣壳在抗原表达和肝转导方面优于AAV-KP1。每组两只动物在给药后3个月表现出持续低水平的huFIX表达，尽管载体拷贝相当，但每组一只动物随时间失去huFIXmRNA和蛋白表达。我们调查了载体附加体中的表观遗传差异是否可以解释这种转录丢失。Cut&Tag分析显示在失去表达的两只动物中激活组蛋白标记的水平较低。当将恒河猴与注射相同载体的小鼠中的rAAV基因组相关组蛋白修饰进行比较时，在猕猴衍生的游离体中，激活的组蛋白标记明显减少。AAV基因组的差异表观遗传标记可以解释小鼠和恒河猴的不同表达谱以及在临床前和人类临床试验中在灵长类动物中观察到的广泛剂量反应变化。
